Force multiplying type cross-bow

ABSTRACT

A multiple-arm cross-bow is provided, the same having an elongate central bowstock portion and a plurality of arms extending on either side of the bowstock. The arms are connected together through a pulley construction by a bow-string and are so arranged that the force of the cocked bowstring is applied to the arrow missile over an elongated distance. When the bow-arms are cocked or bent rearwardly for but a short distance a greater average thrust and a multiplied force will be imparted to the arrow. A thrust is applied to an arrow over a longer relative distance but through a shorter interval of time.

United States Patent [191 Handford [111 3,809,048 [451 May 7,1974

[54] FORCE MULTIPLYING TYPE CROSS-BOW [76] Inventor: Carl E. Handford, 1722 Burning Birch Ln., Mt. Prospect, [11. 60056 [22] Filed: June 20, 1972 [21] Appl. No.: 264,625

[52] US. Cl. 124/25, 124/30 R [51] Int. Cl. F4lb 5/00 [58] Field Of Search 124/25, 30 R, 30 A, 23, 124/24, 41, 3

[5 6] References Cited UNITED STATES PATENTS 2,500,509 3/1950 Bailey 124/25 3,486,495 12/1969 Allen r 124/24 3,161,189 12/1964 Chessman.. 124/24 3,674,001 7/1972 Hitt 124/24 2,870,675 l/1959 Salisbury 124/3 X 3,512,513 5/1970 Griffith 124/41 X Primary Examiner-Richard C. Pinkham Assistant Examiner-William R. Browne [5 ABSTRACT A multiple-arm cross-bow is provided, the same having an elongate central bowstock portion and a plurality of arms extending on either side of the bowstock. The arms are connected together through a pulley construction by a bow-string and are so arranged that the force of the cocked bowstring is applied to the arrow missile over an elongated distance.- When the bow-arms are cocked or bent rearwardly for but a short distance a greater average thrust and a multiplied force will be imparted to the arrow. A thrust is applied to an arrow over a longer relative distance but through a shorter interval of time.

6 Claims, 7 Drawing Figures PATENTEDIIAY 71914 FIG. 4"

FIG. 3

FIG/6 FORCE MULTIPLYING TYPE CROSS-BOW The present invention relates to cross-bows and, more particularly, to a new and improved multiple-arm cross-bow having a series of arms connected together through a pulley arrangement by the bow-string utilized. Rearward idler pulleys may be employed to restrict the girth of the draw-string configuration proximate the latters connection to the arrow or its propellant member.

Cross-bows have been used over a considerable length of time for hunting, target shooting, as well as tactical combat missiles. Great accuracy can be achieved by the weapon by virtue of its stability in use as well as the usual trigger and bowstock sighting structure employed in the cross-bow construction.

Of prime importance, for purposes of accuracy, is to produce as great arrow velocity as possible.

Prior weapons, to the inventors knowledge, have exclusively used single bow-arm constructions. The present invention, in contrast, relates to a novel cross-bow having a plurality of bow-arms disposed on either side of the conventional bowstock. The arms may be made of spring steel, birch or lemon wood, or other suitable, resilient bow-arm material. In the invention an elongate bow-string connects through a pulley construction all of the tips of the bow-arms. Thus, when the bow-string is withdrawn, all of the bow-arms flex rearwardly. Yet, such flexure is for but a slight distance. In the construction, as about to be described, it will be perceived that the bow-string with the bow-arms will be constructed to provide a propelling force to an arrow over a considerable distance of elongate travel as the latter proceeds forwardly along the bowstock groove. Yet, the bowarms themselves flex rearwardly through cocking and forwardly through firing but a small distance. Accordingly, the bow-arms can be made very stiff so as to apply, in their combination, a high propelling force over a considerable propelling distance. This results in a markedly increased missile velocity of the arrow.

In one embodiment of the invention there is provided end connectors or members for the bow tips on either side of the bowstock so that such bow-tips and the bowarms related thereto may move directly in tandem.

Accordingly, a principal object of the present invention is to provide a new and improved bow.

An additional object of the invention is to provide a new and improved cross-bow.

A further object is to provide a multiple-arm crossbow, with the tips of such multiple-arms being connected together through the drawstring such that the bows may operated conjointly to produce a high propelling force over a considerable distance to an arrow being shot.

A further object is to provide an improved cross-bow having multiple-arms connected together to produce a tandem effect as to missile propulsion from such crossbow.

A further object is to provide a multiple-arm crossbow having rigid tip connecting means enabling tandem operation of the multiple-bow arms thereof to produce a high missile velocity relative to arrows being shot.

The features of the present invention may best be understood by reference to the following description taken in connection with the accompanying drawings in which:

FIG. 1 is a plan view of a multiple-arm cross-bow constructed in accordance with the principles of the present invention; rigid elongate end connectors of the bow-arms are shown in a phantom line for convenience of illustration, where such are used.

FIG. 2 is a view of the structure of FIG. 1 when the same is in cocked condition.

FIG. 3 is a transverse cross-section taken along the line 3-3 in FIG. 1. Y

FIG. 4 is a transverse cross-section taken along the line 4-4 in FIG. 1, illustrating a representative mounting of a bow-arm to the bowstock of the invention.

FIG. 5 is an enlarged fragmentary detail of a representative boss connection of the bowstock to the bowarm wherein the same also utilizes a spring steel or other propelling bracket.

FIG. 6 is an enlarged cross-section, taken along the line 6-6 in FIG. 1, and illustrates a representative intermediate pulley mounted.

FIG. 7 is an enlarged section of a representative end of a bow-arm and is taken along the line 7-7 in FIG. 1.

In FIG. 1 elongate bowstock 10 may be made of wood, metal, plastic or other suitable material. In the drawings illustrated, the bowstock is made of a selected hardwood. Bowstock 10 includes plural angulated bosses l 1 integral with the bowstock as to elongate portion 12 thereof. Of course, where the bowstock is made of plastic, then the bow-arm receiving bosses 1 1 may be molded in the general construction. These may comprise separate parts, however, that are pinned or otherwise secured to the bowstock proper.

Each of the resilient bow-arms 13 are made of wood such as birch or lemon wood, or conceivably of metal such as spring-steel, and are pinned in place by pins 14. These may comprise elongate members having a reduced shank 15 and an enlarged threaded head 17 received in the interiorly threaded recess 16 of the insert I. A boss recess 18 accommodates the positionment of the insert I as described.

FIG. 3 illustrates the bowstock'10 and the bosses 1 1 attached to or integrally formed therewith.

A series of pulleys 19 are mounted proximate the ends of the respective bow-arms l3, and which are preferably fabricated as shown at 20 in FIG. 7. Pin axles 21 having nut and washer attachments 22 may be provided for securing these end-pulleys 19 in place. Idler pulleys 23 are also provided and may be secured by a respective bracket 24 or conventional U-shaped form to the individual bosses. Such securement may be accomplished by welding or rivets or by other conventional means. Intermediate pulleys 25 are secured by rectangularly configured brackets 26 to the individual bow-arms medial of their extremities.

Additionally, guide pulleys 27 may be secured by corresponding brackets 28 to the bowstock 10 in any conventional manner as by bolt attachments 29. Optionally, the brackets, of course, may be made integrally with the bowstock material.

Eyelets 30 and 31 may be of conventional form and are fixedly secured to the respective ends 32 and 33 of the forward bow-arms 13A, otherwise similar in construction to bow-arms l3.

In operation, FIG. 1 illustrates the composite crossbow as being in the usual or rest position. When the bow-string 34 is drawn rearwardly, then the resilient bow-arms are tensioned rearwardly to assume their cocked arcuate configuration.

With regard tothe bow-string 34, the same may comprise an integral elongate connector simply attached at its opposite ends to the eyelets 30 and 31.

Arrow receiver 35 may be conventional in form and have a forward recess 36 for receiving the rear extremity of arrows to be shot. The rearwardly convex extremity 37, of course, serves as an abutment for the bowstring.

Whether the bow be manually drawn rearwardly, or otherwise cocked, is of no concern in the present invention. Suffice it to say that a general channel or other type of guide 38 will be supplied longitudinally along the bowstock so as to receive and guide the receiver 35. In FIG. 3 the guide is shown simply as an elongate groove. The trigger mechanism, of whatever form (not shown), will of course engage the receiver 35 when used.

In operation, there is a force multiplying and prolongation factor presented by virtue of the inclusion of the multiplicity of bow-arms on both sides of the bowstock.

This is enhanced upon the incorporation of the rigid elongate members 41 in their pivotal mounting to pulley pins 21 of the several bow-arms. Thus, the brawing back of the bow-string places a tension all bow-arms as these are all drawn rearwardly as shown in H0. 2. As the bow-string is cocked and subsequently released, then each arm is relied upon to impart a force and hence a motion to the arrow being released, and this by the system of pulleys accommodating the bow-string. Each arm, therefore, needs to be drawn rearwardly only a short distance; nonetheless, such an action, by virtue of the pulley system provided, will impart a forward force, exerted upon the arrow, which persists through a substantial distance of arrow travel along the bowstock. The thrust exerted upon the arrow, therefore, is over a considerably longer distance and over a shorter time interval compared to a conventional, single-bow arrangement, thus resulting in the greater missile velocity relative to the arrow.

if desired, .l-configured leaf springs 39 may be secured as by attachment 40 to the bowstock so as to supply an additional bow action for the bow-arms utilizing the same.

It is understood that the trigger mechanism may of course be drawn rearwardly by means of a threaded shaft and crank, by a small block and tackle, by hand, or otherwise. It is further to be noted that bow-arms may be rotated in their respective mounting bosses so they are less apt to develop any permanent warp or set.

What is provided, therefore, is a composite, multiplearm cross-bow wherein, by use of a series of bow-arms provided on either side of the bowstock, a high, long duration, of forward thrust is provided so that any arrow being propelled will be done so through an application of force through a considerable distance, this so as to increase the speed of the arrow as it proceeds from the bow and overcome drag of the bowstock.

While particular embodiments of the invention have been shown and described, it will-be obvious to those skilled in the art the various changes and modifications which may be made without departing from the essential features of the present invention and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.

I claim:

1. A bow construction including, in combination, an elongate bowstock longitudinally oriented in the direction of arrow line-of-flight; a plurality of pairs of longitudinally spaced bow-arms of said bowstock and having their respective tips disposed on, opposite sides of said bowstock, and a sole bow-string connected to all of said bow-arms proximate said tips and extending across said bowstock, whereby when said tips are forced rearwardly by a pull on the bowstring, in a direction opposite to that of intended arrow line-of-flight, all of said bow-arms will be tensioned simultaneously.

2. The structure of claim 1 wherein said bow-arms each include end pulleys at their tips, said bowstock including multiple pulleys respectively disposed proximate the junctures of said bow-arms with said howstock, said bow-string being routed around said pulleys.

3. The structure of claim 2 wherein said bowstock includes idler pulleys disposedrearwardly of the rearmost ones of said bow-arms, said sole bow-string being disposed operably upon and interior of said rearward idler pulleys so that the bow-string will be positioned between said rearward idler pulleys when said howstring is drawn rearwardly to a cocked position.

4. The structure of claim 1 wherein said bowstock includes a plurality of laterally and oppositely positioned bow-arm receiving, unitary hollow bosses, and said bow-arms being seated in and pinned within said bosses.

5. The structure of claim 1 wherein said bowstock includes laterally spaced J-configured spring brackets resiliently engaging respective ones of said bow-arms.

6. A bow construction including, in combination, an elongate bow-stock, a plurality of pairs of bow-arms having their respective tips disposedon opposite sides of said bowstock, a sole bow-string connected to said bow-arms proximate said tips and spanning across said bowstock, a'pair of rigid elongate members, each one of said members being disposed respectively on an opposite side of said bowstock and operably connecting successively the tips of said bow-arms, 

1. A bow construction including, in combination, an elongate bowstock longitudinally oriented in the direction of arrow lineof-flight; a plurality of pairs of longitudinally spaced bow-arms of said bowstock and having their respective tips disposed on, opposite sides of said bowstock, and a sole bow-string connected to all of said bow-arms proximate said tips and extending across said bowstock, whereby when said tips are forced rearwardly by a pull on the bowstring, in a direction opposite to that of intended arrow line-of-flight, all of said bow-arms will be tensioned simultaneously.
 2. The structure of claim 1 wherein said bow-arms each include end pulleys at their tips, said bowstock including multiple pulleys respectively disposed proximate the junctures of said bow-arms with said bowstock, said bow-string being routed around said pulleys.
 3. The structure of claim 2 wherein said bowstock iNcludes idler pulleys disposed rearwardly of the rearmost ones of said bow-arms, said sole bow-string being disposed operably upon and interior of said rearward idler pulleys so that the bow-string will be positioned between said rearward idler pulleys when said bow-string is drawn rearwardly to a cocked position.
 4. The structure of claim 1 wherein said bowstock includes a plurality of laterally and oppositely positioned bow-arm receiving, unitary hollow bosses, and said bow-arms being seated in and pinned within said bosses.
 5. The structure of claim 1 wherein said bowstock includes laterally spaced J-configured spring brackets resiliently engaging respective ones of said bow-arms.
 6. A bow construction including, in combination, an elongate bow-stock, a plurality of pairs of bow-arms having their respective tips disposed on opposite sides of said bowstock, a sole bow-string connected to said bow-arms proximate said tips and spanning across said bowstock, a pair of rigid elongate members, each one of said members being disposed respectively on an opposite side of said bowstock and operably connecting successively the tips of said bow-arms. 